Synthetic Proper Elements for Outer Main Belt Asteroids

Author(s):  
Z. Knežević ◽  
A. Milani
Keyword(s):  
1994 ◽  
Vol 160 ◽  
pp. 143-158 ◽  
Author(s):  
Zoran Knežević ◽  
Andrea Milani

Four perturbation theories presently used to compute asteroid proper elements are reviewed, and their results are briefly discussed (Milani and Knežević, 1990, 1992, 1994, for low to moderate eccentricity/inclination main belt objects; Lemaitre and Morbidelli, 1994, for high e, I objects; Milani, 1993, for Trojans; Schubart, 1982, 1991 for Hildas). The most important recent improvements are described, in particular those pertaining to the upgrades of the previous analytic and semianalytic solutions. The dynamical structure of the asteroid main belt, as defined by the low order mean motion resonances and by linear and nonlinear secular resonances, is considered from the point of view of the effects of these resonances on the accuracy and/or reliability of the computation of proper elements and on the reliability of the identification of asteroid families.


Icarus ◽  
1994 ◽  
Vol 107 (2) ◽  
pp. 219-254 ◽  
Author(s):  
Andrea Milani ◽  
Zoran KnežEvić

1994 ◽  
Vol 160 ◽  
pp. 467-470
Author(s):  
Andrea Milani ◽  
Edward Bowell ◽  
Zoran Knežević ◽  
Anne Lemaitre ◽  
Alessandro Morbidelli ◽  
...  

We have assembled the asteroid proper elements computed by different authors, using different methods, and for different regions of the asteroid belt. Asteroids on planet crossing orbits are not yet included. The use of very different algorithms is dictated by the dynamics of the different regions. For the asteroids of the main belt, having semimajor axes between 2.1 and 3.8 AU, and with proper eccentricity and sine of inclination less than 0.3, proper elements are computed by a fully analytical iterative theory developed by Milani and Knežević (1990,1992,1994; hereafter M&K). For high inclination and/or eccentricity main-belt asteroids, having 1.8 < a < 3.8 AU and either e or sin I larger than 0.24, proper elements are computed by a semianalytical theory developed by Lemaitre and Morbidelli (1994; hereafter L&M). For Trojans, proper elements are computed by a synthetic theory (that is, from the output of a numerical integration for a few Myr) by Milani (1993). For the Hilda asteroids in the 3: 2 resonance, proper elements have been computed by a synthetic theory by Schubart (1982, 1991). For a discussion of the state of the art in the computation of proper elements, see Knežević and Milani, this volume; for Trojans, see Milani, this volume; for some other cases (e.g. proper elements for resonant asteroids), see Froeschlé and Morbidelli, this volume. When and if new proper elements will be available for other asteroids, they will be added to the public domain file, together with updates and upgrades of the existing catalogues.


2015 ◽  
Vol 10 (S318) ◽  
pp. 46-54 ◽  
Author(s):  
Bojan Novaković ◽  
Georgios Tsirvoulis ◽  
Stefano Marò ◽  
Vladimir Đošović ◽  
Clara Maurel

AbstractWe consider the role of the dwarf planet Ceres on the secular dynamics of the asteroid main belt. Specifically, we examine the post impact evolution of asteroid families due to the interaction of their members with the linear nodal secular resonance with Ceres. First, we find the location of this resonance and identify which asteroid families are crossed by its path. Next, we summarize our results for three asteroid families, namely (1726) Hoffmeister, (1128) Astrid and (1521) Seinajoki which have irregular distributions of their members in the proper elements space, indicative of the effect of the resonance. We confirm this by performing a set of numerical simulations, showcasing that the perturbing action of Ceres through its linear nodal secular resonance is essential to reproduce the actual shape of the families.


1994 ◽  
Vol 160 ◽  
pp. 159-174
Author(s):  
Andrea Milani

The state of the art in the dynamics of the Trojan asteroids has progressed rapidly, since it has been possible to perform numerical integrations of many orbits for millions of years. Accurate proper elements are now computed by the synthetic method, that is from the output of a numerical integration; their stability, at least for time spans of a few million years, is good. This has allowed identification of Trojan families with an automated procedure closely mimicking the one used in the main belt. Although the families identified in a reliable way are only four, the occurrence of significant collisional evolution, not unlike that of the main belt, can be confirmed. The dynamical structure of the Trojan cloud, including the location of the main secular resonances, can be deduced from the proper elements and frequencies by a simple fit. However, many problems are not solved: the origin of a significant percentage of chaotic orbits showing no indications of instability; the location of the stability boundary of the Trojan cloud; the origin of the high inclination of most Trojans. We also do not know if there are “Trojans” for some other planets beside Jupiter: only one Mars Trojan has been found.


2020 ◽  
Vol 499 (3) ◽  
pp. 3630-3649
Author(s):  
Timothy R Holt ◽  
David Vokrouhlický ◽  
David Nesvorný ◽  
Miroslav Brož ◽  
Jonathan Horner

ABSTRACT Asteroid pairs, two objects that are not gravitationally bound to one another, but share a common origin, have been discovered in the Main belt and Hungaria populations. Such pairs are of major interest, as the study of their evolution under a variety of dynamical influences can indicate the time since the pair was created. To date, no asteroid pairs have been found in the Jovian Trojans, despite the presence of several binaries and collisional families in the population. The search for pairs in the Jovian Trojan population is of particular interest, given the importance of the Trojans as tracers of planetary migration during the Solar system’s youth. Here we report a discovery of the first pair, (258656) 2002 ES76 and 2013 CC41, in the Jovian Trojans. The two objects are approximately the same size and are located very close to the L4 Lagrange point. Using numerical integrations, we find that the pair is at least 360 Myr old, though its age could be as high as several Gyrs. The existence of the (258656) 2002 ES76–2013 CC41 pair implies there could be many such pairs scattered through the Trojan population. Our preferred formation mechanism for the newly discovered pair is through the dissociation of an ancient binary system, triggered by a sub-catastrophic impact, but we can not rule out rotation fission of a single object driven by YORP torques. A by-product of our work is an up-to-date catalogue of Jovian Trojan proper elements, which we have made available for further studies.


1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.


2021 ◽  
Vol 366 (6) ◽  
Author(s):  
Wutong Gao ◽  
Jianguo Yan ◽  
Weitong Jin ◽  
Chen Yang ◽  
Linzhi Meng ◽  
...  

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Maddalena Mochi ◽  
Giacomo Tommei

The solar system is populated with, other than planets, a wide variety of minor bodies, the majority of which are represented by asteroids. Most of their orbits are comprised of those between Mars and Jupiter, thus forming a population named Main Belt. However, some asteroids can run on trajectories that come close to, or even intersect, the orbit of the Earth. These objects are known as Near Earth Asteroids (NEAs) or Near Earth Objects (NEOs) and may entail a risk of collision with our planet. Predicting the occurrence of such collisions as early as possible is the task of Impact Monitoring (IM). Dedicated algorithms are in charge of orbit determination and risk assessment for any detected NEO, but their efficiency is limited in cases in which the object has been observed for a short period of time, as is the case with newly discovered asteroids and, more worryingly, imminent impactors: objects due to hit the Earth, detected only a few days or hours in advance of impacts. This timespan might be too short to take any effective safety countermeasure. For this reason, a necessary improvement of current observation capabilities is underway through the construction of dedicated telescopes, e.g., the NEO Survey Telescope (NEOSTEL), also known as “Fly-Eye”. Thanks to these developments, the number of discovered NEOs and, consequently, imminent impactors detected per year, is expected to increase, thus requiring an improvement of the methods and algorithms used to handle such cases. In this paper we present two new tools, based on the Admissible Region (AR) concept, dedicated to the observers, aiming to facilitate the planning of follow-up observations of NEOs by rapidly assessing the possibility of them being imminent impactors and the remaining visibility time from any given station.


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